Power tools such as table saws, vertical saws, planers, miter saws, circular saws, band saws, and the like are used in the construction and wood working industries. When a saw blade of a table saw or a cutterhead of a planer comes in contact with a workpiece, e.g., a piece of lumber, to cut the workpiece, the height and angle of the blade relative to the workpiece determines the depth and angle of cut into the workpiece. Because workpieces vary significantly in size and desired cut types, it is advantageous to make saw blades adjustable relative to the work surface of the table saw, and thus adjustable relative to the workpiece supported by the work surface. An example of a table saw with a height adjustment mechanism is depicted in FIG. 1 (titled “Prior Art”).
A table saw 10 depicted in FIG. 1 includes a table top 12 with a saw blade opening 14 formed therein. The saw blade 16 extends through the saw blade opening 14 and is configured to rotate about a rotation axis where it is coupled to a motor shaft (not shown). The table saw 10 further includes an on/off switch 18 and a support arrangement 20. The saw blade 16 is configured to cut a workpiece by turning about the rotation axis in a direction depicted by arrow 22 when operated by a saw blade rotation motor (not shown). The particular position of the saw blade 16 relative to the table top 12 is adjusted by rotating a hand wheel 24, which is mounted to a shaft of a support assembly mounted in the support arrangement 20 as described below in more detail.
The hand wheel 24 interacts with bevel gears or a rack and pinion of the table saw 10 to adjust the position of the saw blade 16. However, adjustment of the saw blade 16 using a hand wheel 24 that interacts with bevel gears is difficult because the bevel gears can get jammed with sawdust generated by the table saw 10 during cutting operations. Additionally, adjustment of the saw blade 16 using a hand wheel 24 that interacts with a rack and pinion is difficult because the gears or the rack and pinion are configured with allowances, also known as backlash, which provide some play between the rack and pinion and, therefore, reduce positional accuracy of the saw blade 16. The primary objective of the present disclosure, therefore, is to provide a height adjustment mechanism for a power tool which eliminates the need for bevel gears or a rack and pinion.